v0.4.0 - Public release preparation

Major changes:
- Moved to gitlab.com/andunn/ihe
- Added MIT license (GitLab copyright)
- Added Dockerfile and container CI pipeline
- Converted all visualizations to canvas for performance
- Added Methodology section with LaTeX formulas and pseudocode

New features:
- Section Coverage now works across all granularities
- Redundancy Candidates shows content excerpts
- Git history resolves symlinks correctly
- Radial compression chart and radar diversity chart

Cleanup:
- Removed legacy Observable Framework files
- Simplified README and AGENTS.md
- Updated module path and all Go imports

Screenshot demo uses Anthropic's official Claude Code plugins.